The Pergamon Museum in Berlin houses reconstructed monumental buildings from Pergamon, Turkey, including the Pergamon Altar. It took 20 years to construct the museum from 1910 to 1930. The museum was damaged in World War 2 but many artifacts were stored safely. Some pieces remained in Russia and there is an agreement for their return, but Russian laws currently block it. The museum attracts over 850,000 visitors annually, making it Germany's most visited art museum.